The present invention relates to stage construction and more particularly to stage installations providing remote controlled movement of stage elements such as scenery, furniture and the like.
For theatrical productions, it is common to have a temporary floor containing mechanical systems to move scenery laterally, vertically, and rotationally within the stage area. These floors are known as show decks and are often six to twelve inches high and rest directly on the permanent stage floor of a venue. Within a show deck the most common means for moving rolling scenic units laterally across the floor are winch driven tracks. Deck tracks regularly consist of a xe2x85x9cxe2x80x3 slot in the deck surface under which a steel block known as a dog travels in a tunnel built into the show deck. The scenic unit connects to the dog with a xc2xcxe2x80x3 wide vertical steel bar known as a knife that passes through the xe2x85x9cxe2x80x3 slot in the floor surface and is captured in the dog. The dog is then pulled through the tunnel by a continuous loop of aircraft cable that spools on and off of an electric winch near or below the show deck.
The main drawback of cable driven tracks is the inability to cross them. This problem has existed since the Italians developed rope driven deck tracks in the sixteenth century. The dog in one tunnel will always collide with the permanent cables in the intersecting track tunnel, which are always present regardless of the location of the intersecting dog or scenic unit is located along its travel path. As theatrical designers lay out the show decks to coordinate how the scenery moves and stores, they are often frustrated by the challenge of keeping each track separate. In most cases they compromise their design intent to accommodate the physical realities and this results in less functionality and artistic impact than ultimately desired.
In recent years, there have been several attempts to mitigate the problem by combining standard cable driven tracks with other technologies. These alternates include friction driven scenic units which have positioning and cable management problems, and push chain driven tracks which have noise problems and excessive costs.
It is the object of the present invention to provide a novel stage element movement assembly for location below the surface of the stage deck which permits crossing tracks for the movement of multiple stage elements.
It is also an object to provide such an assembly which can be fabricated relatively simply, installed relatively quickly and operated efficiently to move stage elements in different directions which cross.
Another object is to provide a novel stage installation containing such a novel movement assembly which enables movement of multiple stage element through the same stage area.
It has now been found that the foregoing and related objects may be readily attained in a stage element movement assembly for location below the surface of a stage deck and a first cable for disposition in a tunnel below the stage deck and extending in a first path in a first direction. A first dog is secured to the first cable for movement therewith in the tunnel, and an engagement member is engaged with the first dog and adapted to extend upwardly through a slot in the stage deck for engagement with the stage element to be moved. A power driven winch is provided for moving the first cable and first dog in the first path.
A second cable is provided for disposition in a tunnel below the stage deck extending in a second path in a direction at an angle to the direction of the first cable and crossing below the first cable. Linearly spaced cable guide rollers are provided on opposite sides of the cable crossing and the second cable passes thereabout. The rollers cause the cable to be moved downwardly from the plane of its path to pass below the first cable and thereafter cause the cable return to move upwardly to the plane of its original path. A pair of engagement elements are secured to the second cable in spaced relationship and engage a crossing dog which has spaced engagement elements on its lower surface for engagement elements on the second cable to effect driving action of the crossing dog by the second cable. The leading one of the engagement elements on the second cable disengages from the crossing dog as the second cable is moved downwardly by the guide rollers while the trailing engagement element remains engaged until it is moved downwardly by the guide rollers. At this time, the leading engaging element reengages the crossing dog as the cable returns to its original path. An engagement member is engaged with the crossing dog and extends upwardly through a slot in the stage deck for engagement with a stage element to be moved, and a power driven second which is provided for moving the second cable and crossing dog in the second path.
Preferably, the rollers are supported in a fixture located below the deck and includes cable guide means guiding the second cable in the fixture about the rollers. The engagement elements on the crossing dog are recesses on its lower surface into which the cable engagement elements seat.
Generally, the assembly includes elongated track members along the paths of the cables providing a channel in which the cable and dogs move and having an opening at their upper end through which the engagement members extend. The cables are endless and there are included sheaves in the paths and about which the cables extend.
The engagement elements on the crossing dog are spaced apart a distance equivalent to the spacing between the engagement elements on the second cable, and the first dog and crossing dogs are spaced on their respective cables so as to preclude their meeting at the crossing. Preferably, the path of the second cable is perpendicular to the path of the first cable.